docs: def trt_pmf(matrices):
      """
      Fold full disaggregation matrix to tectonic region type PMF.
  
      :param matrices:
          a matrix with T submatrices
      :returns:
          an array of T probabilities one per each tectonic region type
      """
      ntrts, nmags, ndists, nlons, nlats, neps = matrices.shape
      pmf = numpy.zeros(ntrts)
      for t in range(ntrts):
          pmf[t] = 1. - numpy.prod(
              [1. - matrices[t, i, j, k, l, m]
               for i in range(nmags)
               for j in range(ndists)
               for k in range(nlons)
               for l in range(nlats)
               for m in range(neps)])
      return pmf